diff --git a/boot.py b/boot.py
new file mode 100644
index 0000000..9faaae5
--- /dev/null
+++ b/boot.py
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+# boot.py -- run on boot-up
+# can run arbitrary Python, but best to keep it minimal
+
+import pyb
+#pyb.main('main.py') # main script to run after this one
+#pyb.usb_mode('CDC+MSC') # act as a serial and a storage device
+#pyb.usb_mode('CDC+HID') # act as a serial device and a mouse